The UN climate talks COP30 have been evacuated due to a fire breaking out inside the venue in Belém, Brazil.
BBC journalists saw flames and smoke in the pavilion area before they were rushed outside where fire engines raced past.
The Brazilian government says that the fire is now under control and that no-one has been injured.
Orange flames burned a hole through the sheeting that covers the venue, which is in a former aerodrome. One video shows a man spraying a fire extinguisher at the fire before running away.
It is not yet known what caused the blaze. One eyewitness told the BBC that he believes an electrical fire was the cause.
Hundreds of people are now sitting on the floor or on plastic chairs outside in high temperatures and humidity.
A woman was taken away in a wheelchair, but it is not clear if that was connected to the fire.
A number of country delegations were forced to take shelter outside under the roof of a petrol station, a member of the UK delegation told the BBC. He said the fire has halted negotiations.
The UN, which runs COP climate meetings, said the fire brigade is checking the venue to assess safety and that the summit has been temporarily taken over by Brazilian authorities.
Thousands of people are attending the UN climate talks, including members of delegations from around the world.
Nearly 200 countries are trying to agree on how to make progress in tackling climate change.
The BBC has asked the UN for more information about the cause of the fire and any impacts.